Electrical protective device.



A. W. COPLEY & B. H. SMITH.

ELECTRICAL PROTECTIVE DEViCE.

APPLICATION FILED JUNE 30, I916.

1,286,290 Patented Dec. 3, 1918.

2 SHEETSSHEET 1.

WITNESSES: INVENTORS ATTORNEY A. W. COPL'EY & B. H SMITH.

ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED JUNE 30, 1916.

1,286,239. 7 Patented Dec. 3, 1918.

2 SHEETS-SHEET 2- Fig.5.

WITNESSES:

INVENTOR5 Almon M Copley 8 Benjamin H. Smith" ATTORNEY ALMQN' W. COPLEY,F PITTSBURG ENJAMIN H. M1 H, GE TURTLE CREEK,

PENNSYZVANIA, ASSIGNORS T0 WESTINGHOUSE ELECTRIC AND MANUFACTURINGCQMPANY, A CORPORATION 0F PENNSYLVANIA.

Application illed June 30, 1916.

T 0 all whom it may concern:

Be it. known that we, Amrou W. Corner, a citizen of the United States,and a resident of Pittsbur h, in the county of Allegheny and State ofPennsylvania, and BENJAMIN H. SMITH, a citizen of the United States, anda resident of Turtle Creek, in the county of Allegheny and State onPennsylvania, have invented a new and useful Improvement in ElectricalProtective Devices, or which the following specification is acontinuation in part of copend ing application Serial No. 771,888, tiledJune 5, i913,

@ur invention relates to electricai protective devices and particularlyto relays. One object of our invention is to provide a time-limit relayhaving electrical means for obtaining its time-limit functions.

Another object of our invention is to provide a relay of the aboveindicated character that shali have an inverse time-iimit for all valuesof current up to a predetermined and a definite time-limit for all.values of curr nt above the predetermined value.

A further object our invention is to provide a relay ofthe aboveindicated character that shall have means whereby a definite time-limitmay be obtained for all values of current at which the device is adaptedto operate.

@ur present application is a continuation, in part, of our copendingapplication, Serial No. 771,888, filed June 5, 1913. e

In the carrying out of our invention, we provide a magnetizable coremember, an armature, main and auxiliary windings-and a saturabletransformer so connected between the two windings that, according to thevalue or the current at whichit becomes saturated, the torque of thearmature may be so regulated that it may be constant for all values ofcurrent traversing the main winding, or it may vary substantially as thecurrent traversing the main Winding up to a predetermined value ofcurrent and be substantially constant above the predetermined value ofcurrent.

the accompanying drawings Figure l is a diagrammatic view oi a relayembodying our invention, and Figs. 2 and 3 are diagrammatic views ofmodified forms of relays embodying our invention.

Specification of Letters Patent.

Patented Dec. 3, 1918,

Serial no. looses.

A relay 1 is operatively connected to an electric circuit 2 andcomprises, in general, a magnetizable core member 3, a rotatablearmature i, a main winding 5, a secondary winding '3, auxiliary windings7 and a saturable transformer 8.,

The armature A- is mounted upon a shaft 9 upon which is also mounted amovable bridging contact member 10 that is adapted to engage twostationary contact members 31 which constitute the terminals of atripping device (not shown). The inner end of a relatively light spring12 is operativcly connected to the shaft 9 and its outer end isconnected to a stationary member 13. The armature 1- is adapted to turnbetween the poles of permanent magnets 14 for the purpose of damping orretarding its move; ments. The main winding 5 of the relay It isoperatively connected the secondary winding 15 of a current transformer16, and the secondary winding 6 of the relay 1 is operatively connectedto a primary winding 1? of the saturable transformer 8. A secondarywinding 18 of the transformer 8 is operatively connected to theauxiliary windings 7 of the relay.

l-Vhen a predetermined overload occurs upon the circuit 2, currentproportional to the current, that traverses the circuit 2 will traversethe main winding 5 of the relay and this current will induce a voltagein the secondary winding 6 which, by reason of the closed-circuitrelation with the winding 17 of the transformer 8, will cause a currentto traverse the winding 17. The current traversing the winding 17 willinduce a voltage in the winding 18 and this will cause current totraverse the auxiliary windings 7 of the relay. Thus, a shifting flingis set up in the air gun of-the relay 1 that'causes the armature d toturn against the action of the spring 12 to eiiect engagement betweenthe bridging contact member 10 and the stationary contact members 11.The flux that causes the armature to turn may be assumed to be composedof two parts, one substantially proportional to the current traversingthe circuit 2 and the other substantially constant by reason oi thepartial m'agnetic'saturation of the transformer 8. Thus, the armatureiwill develop a torque substantially proportional to the currenttraversing the lit) Cid

winding 5, under predetermined conditions.

Hqwever. if the transformer 8 is worked winding above t 1e nice o itssatuiartioni aevwthe'nga phase-angular relation between the two fluxesis materially reduced and, thus, the torque of the armature i willdecrease. Consequently, at a predetermined value of current, dependingupon the magnetic saturation of the transformer S, the torque developedby the armature will become substantially constant for all values ofcurrent traversing the winding 5. That, -is to say, the time requiredfor the contact member 10 to engage the contact members 11, after,

a predetermined overload traverses the-circuit 2, will varysubstantially inversely as the current traversing the circuit 2, up to apredetermined overload,a nd will be substantially constant for allvalues of overload above the predetermined value.

In Fig. 2 of the drawings, the magnetizable core member 3 is providedwith a magnetizable armature 19 that is supported by springs 20. Thearmature 19 is provided with contact members 21 that are adapted toengage stationary contact members 22 for the purpose of closing thecircuit between the winding 6 of the relay 1 and the winding 17 of thetransformer 8, under predetermined conditions.

ln Fig. 2 of the drawings, when a predetermined overload occurs upon thecircuit 2, sutiicient current will traverse the main winding 5 to movethe armature 19 downwardly. Thus, the armature i will not creep oroperate until the contact members 21 and 22 are engaged. if the currentrequired to operatethe armature is of such value as to induce sufficientvoltage in the winding ii to cause the transformer 8 to be saturatedabove the knee of its saturation curve, it will be understood that thetorque developed by the armature i will be substantially constant. Inother words, the armature 19' is provided for the purpose of socontrolling the windings of the relay that the contact member 10 willengage the contact members 11 in a definite time, irrespective of theoverload traversing the circuit '2.

in Fig. 3 of the drawings, the armature 19 is provided with a contactmember 23 that is adapted to be normally held in engagement with astationary contact member '24 by the spring 20. T he contact members 23and 24 constitute the separable terminals of a short-circuit connection25 across the terminals of the winding 17 of the transformer 8.

hen a predetermined overload occurs upon the circuit 2' and themodified, form or our invention shown in Fig. 3 is employed, thearmature 19 will be moved downwardly to open the short-circuitconnection 25 around the winding 17 to thus permit the winding 18 toenergize the auxiliary windnasaase ings 7 which, in connection with themain 5, cause the armature 4 to turn n of a li ht resetting spring (notshown) with a, substantia onstant torque, substantially as set forthwith respect to the device shown in Fig. 2 of the drawings.

It will be understood that, if the arma' ture 19 is omitted from themodified forms of our invention, shown in Figs. 2 and 3, the deviceswill operate in substantially the same manner as the device shown inFig. l of the drawings. It will be further understood that the time'required for the contact members 10 and 11 to engage may be changed byvarying. the size of the core and the number of turns of the windings ofthe transformer 8 in order that it may become saturated. underpredetermined conditions. Thus, the .time of operation of the relay maybe either definite under all .con ditions or inverse up to apredetermined value of current and definite for all values of currentabove the predetermined value.

We do not limit our invention to the particular arrangementsillustrated, as it may be variously modified without departing torque tobe exerted on the armature for all j values of current traversing themain winding above a predetermined value.

g A. relay comprising a magnetizable core member having a main and anauxiliary winding thereon, an armature, anda reactance device connectedbetween the main and auxiliary windings for causing the armature todevelop a constant torque for all values of current traversing the mainwind ing above a predetermined value.

3. A motor comprising a .magnetizable core member-having a main and anauxiliary winding thereon, an armature and means connected in circultwith the said auxiliary winding to cooperate with the main winting tocause the armature to develop a substantially constanttorque whencurrent in excess of a predetermined value traverses the main winding. Y

i. A relay comprising a magnetizable core member having a main and anauxiliary winding thereon, an armature and electrical means connected incircuit with the said auxiliary winding to cooperate with the mainwinding to cause the armature to develop a substantially constant torquewhen the current traversing the main winding exceeds a predeterminedvalue.

5. A relay comprising a magnetizable core ire QUE

member having a main and an auxiliary winding thereon. an armature andmeans interposed in the circuit oi the said auxiliary winding thatcooperates with the said main Winding to cause the armature to develop asubstantially constant torque when the cur rent. traversing the mainwinding exceeds a prtaletermined value.

(3. A. relay comprising a magnetizable core member having a main and anauxiliary winding thereon. an armature and a reactor interposed in thecircuit of the said auxiliary winding that cooperates with the mainwincling to -ause the armature to develop a substantially constanttorque when the current traversing the main winding exceeds apredetermined value.

7. 3i relay comprisinga magnetizable core member having a main winding.an auxiliary winding and a secondary winding thereon. and a normallymagnetically saturated transformer having two windings thereon, one ofthe transformer windings being connected in circuit with the auxiliarywinding and the. other transformer winding being connected in circuitwith the said secondary windin S. A relay comprising an armature, a mainwinding. an auxiliary winding. and a transformer associated with thesaid windings and adapted to become magnetic-ally saturated when apredetermined current traverses the main winding to cause the armatureto develop a substantially constant torque for all values oi current inthe main winding above the predetermined value;

9. A relay comprising a maguetizable core member having a main and anauxiliary winding thereon. an armature, a magnet-i- -ally saturabletransformer interposed between the said main winding and the saidauxiliary winding and means dependent upon the current traversing themain winding for controlling the circuit of the auxiliary winding.

10. A relay comprising a magnetizable core member having a main and anauxiliary winding thereon, an armature, meansconnected in circuit withthe said auxiliary winding to coope ate with the main winding to causethe armature to develop a substantially constant torque when the currentin the main winding exceeds a predetermined value. and means dependentupon the current traversing the main winding for controlling the circuitof the auxiliary winding.

11. A relay comprising an armature, a magnetizable core member. a mainwinding and an auxiliary winding disposed on the core member, and atransformer interposed between the main and auxiliary windings andadapted to become saturated under predetermined conditions to cause thearmature to develop a substantially constant torque under thesepredetermined conditions.

12. L relay comprising an armature. a main winding. an auxiliarywinding. and means connected between the said windings whereby asubstantially constant. torque is exerted upon the armature when thecurrent traversing the main winding exceeds a predetermined value.

13. A relay comprising an armature. a main .vinding. an auxiliarywinding. and means operatively connected between the auxiliary and mainwindings whereby a substantially constant torque is exerted upon thearmature when the current traver ing the main winding exceeds apredetermined value.

ll. )1 relay for an electric circuit comprising an armature. windingstherefor and means connected between the windings for causing thearmature to develop a torque that varies substantially directly as thecurrent traversing the circuit up to apredetermined value of current anda substantially definite torque above the predetermined value ofcurrent.

15. Si relay comprising an armature, a.

main winding. an auxiliary winding and means operatively connectedbetween the said windings whereby a torque is exerted on the armaturethat varies directly as the current traversing the main winding up to apredetermined value and a substantially constant torque is exerted uponthe armature above. the predetern'iined value of current.

16. A relay for an electric circuit comprising a magnetizable coremember having two cooperating windings thereon. an armature. and meansconnected between the two windings whereby a torque is exerted on thearmature. in accordance with the current traversing the circuit up to apredetermined value and a constant torque is exerted thereon for allvalues of current traversing the circuit above the predetermined valueof current.

17. A. relay comprising a magnetizable core member having a main and anauxiliary winding thereon. an armature and electrical means connected incircuit with the said auxiliary winding for causing a constant torque tobe exerted on the armature for all values of current traversing the mainwinding above a predetermined value.

In testimony whereof. we have hereunto subscribed our names this 29thday of June. 1916.

ALBION Vv'.-COPLEY. BENLXMIN H. SMITH.

